Consol Energy extinguished the fire in its Blacksville No. 2 coal mine in southern Greene County along the Pennsylvania-West Virginia border and plans to re-enter the mine Wednesday.
The fire has idled work at the mine since it was discovered March 12.
The Cecil-based coal and gas company said Monday that it has been continuously monitoring the atmosphere in the mine and has received approval to re-enter it from federal and state mine agencies and the United Mineworkers.
Consol was able to put out the fire by pumping more than a million gallons of water into the mine through bore holes drilled from the surface about 1,000 feet into the mine.
About 650 miners work at the full-extraction deep mine.